Air atomizing nozzle



March 21, 1967 R. G. GRUNDMAN AIR ATOMIZING NOZZLE Filed Jan. 7, 1965INVENTOR RIC/lord 6.

Grundman ATTORNEY United States Patent 3,310,240 AIR ATOMIZING NOZZLERichard G. Grundman, Grand Rapids, Mich., assignor to General MotorsCorporation, Detroit, Mich., a corporation of Delaware Filed Jan. 7,1965, Ser. No. 424,037 2 Claims. (Cl. 239-404) This invention relatesgenerally to air atomizing nozzles, and more particularly to anatomizing nozzle assembly of the type employing an auxiliary fluid tofacilitate atomization.

Conventional nozzles of the air atomizing type in which an auxiliaryfluid under pressure, such as air, steam, or other suitable gas, is usedto facilitate breaking up a liquid into discrete particles havepresented various difliculties. Among these difficulties has been theinability of the known nozzles to consistently break up the liquid intosmall discrete particles, thus appreciably affecting the efliciency ofthe nozzle. A further difficulty encountered with conventional nozzleshas been the inability of such nozzles to obtain spray patternssufficiently symmetrical about the axis of the nozzle. A still furtherdisadvantage of such prior art devices has been their failure to excitethe liquid to be atomized and the atomizing fluid prior to beingintroduced into their respective discharge orifices, thereby reducingthe ultimate atomization to be realized from the nozzle.

It is the primary object of this invention to overcome such heretoforeencountered difiiculties by providing an air atomizing nozzle whichutilizes air in a highly eflicient manner to produce a high degree ofatomization of fluid over a wide range of viscosities and flow rates.

It is a further object of this invention to provide an atomizing nozzlehaving its air flow passages arranged to effect a high degree ofatomization of liquid fuel while having a secondary affect of supplyingcombustion air to the center of a combustion chamber. 7

A still further object of this invention is the provision of a multiplestage atomization nozzle which results in a more thorough and eflicientatomization of the liquid being atomized.

The present invention overcomes heretofore encountered difficulties andfulfills the above cited objects by providing an air atomizing nozzlewhich atomizes a liquid fuel in a first stage by introducing apressurized air stream into the center of the liquid fuel as it passesinto a diverging discharge orifice from a swirl chamber. Furtheratomization of the resulting fuel-air mixture is effected in a secondstage by impinging air emitted from a swirl chamber into a dischargeorifice surrounding the outlet of the diverging discharge orifice.

The above objects and advantages of the invention will be more clearlyunderstood from the following specifica tion having reference to theaccompanying drawing, wherein:

FIGURE 1 is a sectional view of an atomizing nozzle showing thecomponents of the subject invention in an assembled relationship.

FIGURE 2 is an enlarged fragmentary section of the discharge end of thenozzle.

FIGURE 3 is a sectional view taken substantially along lines 33 ofFIGURE 2 showing the tangential relationship of the fuel and air portsto their respective swirl chambers,

Referring now in detail to the drawing, and initially to FIGURE 1, anair atomizing nozzle assembly embodying the subject invention includes abody member 1 having a fuel supply passage 2 and an air supply passage 3formed therein. The fuel supply passage 2 communicates with a fuelsupply connection 4 while the air supply passage 3 communicates with anair supply connection 5, both the fuel and air supply connections beingsecured to the body member 1 in a conventional manner.

The body member 1 includes a chamber 6 in the fuel supply passage 2 toreceive a valve assembly designated generally at 7. The valve assembly 7is retained within chamber 6 by a coil spring 8 and the fuel supplyconnection 4 and forms no part of this invention.

Body member 1 has an outer face 9 which abuts an end face 10 of astepped cylindrically shaped outer sleeve member 11. A chamber 12 isformed between the body member 1 and the outer sleeve member 11 andconnects with the air supply passage 3 in the body member 1 and one ormore longitudinal air passages 13 provided in the outer sleeve member11.

An annular groove 14 in the end face 10 of the outer sleeve member 11connects with the fuel supply passage 2 in the body member 1 and one ormore diagonal fuel passages 15 formed in the outer sleeve member 11.

The outer sleeve member 11 has an axial cylindrical bore 16 to receivean inner sleeve member 17. The inner sleeve member 17 has a steppedouter cylindrical surface with a cylindrical portion 18 having adiameter which allows it to be pressed or otherwise suitably secured inthe outer sleeve member 11.

Referring now to FIGURE 2, an axial flow air passage 19, formed in theinner sleeve member 17, connects with the chamber 12, shown in FIGURE 1,and terminates in a discharge orifice 20. An inner nozzle washer 21abuts an end face 22 of the outer sleeve member 11 and has an annularextended portion 23 thereon which eX- tends into the cylindrical bore 16and cooperates with the inner sleeve member 17 and the inner bore 16 todefine an annular chamber 24 therebetween, Chamber 24 receives fuel fromthe fuel passages 15 in the outer sleeve member 11.

The inner nozzle washer 21 includes an axial cylindrical bore 25 whichreceives a cylindrical portion 26 of inner sleeve member 17. Thecylindrical bore 25 terminates in an outwardly diverging dischargeorifice 27 which is formed in an extended portion 28 of the inner nozzlewasher 21. The diverging discharge orifice 27 is axially aligned withthe bore 25 and connected thereto by a conical surface section 29. Thecylindrical bore 25 and conical surface 29 surround a reducedcylindrical portion 30 of the inner sleeve member 17 in axial alignmenttherewith and cooperate with the cylindrical portion 30 to form anannular swirl chamber 31 therebetween. An annular space 32 between thecylindrical portion 30 of the inner sleeve 17 and the conical surface 29provides an annular discharge passage for the liquid emitted from theswirl chamber 31 as it enters diverging discharge orifice 27. Aplurality of ports 33, tangentially disposed to the swirl chamber 31 toallow fuel from the annular chamber 24 to be tangentially introducedinto the swirl chamber 31, are provided in the annular extended portion23 of the inner nozzle washer 21.

The cylindrical portion 30 of the inner sleeve member 17 has a dischargeend 34 which is positioned in close proximity to the throat section 35of the diverging discharge orifice 27 such that the fuel emitted fromthe swirl chamber 31 through the annular passage 32 is subjected toimpinging air emit-ted from the discharge orifice 20 of inner sleevemember 17.

An annular groove 36 is formed between the end face 22 of the outersleeve member 11 and the adjacent face of inner nozzle washer 21 toconnect with the air passages 13 in the outer sleeve member 11 and aplurality of ports 37 provided in the inner nozzle washer 21.

An outer nozzle washer 38 abuts inner nozzle washer 21 and has an axialcylindrical discharge orifice 39 therethrough. A conical surface 40 ofthe outer nozzle washer 38 cooperates with an outer surface portion 41of the inner nozzle washer 21 no form an annular swirl chamber 42therebetween. The ports 37 in the inner nozzle washer 21 aretangentially disposed to the swirl chamber 42 to allow air to betangentially introduced into the swirl chamber 42.

The discharge orifice 39 surrounds the diverging discharge orifice 27 ofthe inner nozzle washer 21 and is axially aligned therewith. Thediameter of the discharge orifice 39 is greater than the outer diameterof the extended portion 28 of the inner nozzle washer 21 so as to forman annular passage therebetween.

In assembled position, the outer end of the extended portion 23 of theinner nozzle washer 21 terminates at a point axially inward from theouter end 43 of the discharge orifice 39 in the outer nozzle washer 38.

Referring again to FIGURE 1, a cap member 44 has an inner surfaceadapted to engage the outer peripheral surfaces of the outer sleevemember 11, the inner nozzle washer 21, and the outer nozzle washer 38. Athreaded portion 45 on the cap member 44 is adapted to engage a matingthreaded portion 46 provided on \the body member 1. A radially inwardlydirected portion 47 of the cap member 44 abuts an outer face 48 of theouter nozzle washer 38 to secure the outer nozzle washer 38, the innernozzle washer 21, and the outer sleeve member 11 in axial alignmentagainst the end face 22 of the body member 1 when the cap member 44threadedly engages the body member 1.

In operation, liquid fuel is supplied to the fuel inlet connection 4from an external source and passes through the fuel inlet passage 2' inbody member 1 where it is introduced into fuel passages 15 in the outersleeve member 11. The fuel flows into annular chamber 24 from which itpasses into tangential ports 33 and into the swirl chamber 31. intoswirl chamber 31 causes the fuel to swirl and be emitted from the swirlchamber in a turbulent state. As the swirling turbulent fuel passes intothe outwardly diverging discharge orifice 27, air under pressure whichhas been supplied through air supply passage 3 and axial flow airpassage 19 is emitted from the discharge orifice 20 and impinges theturbulent fuel centrally of its flow path. As the fuel and air mixturepasses through diverging discharge orifice 27, the pressure drop acrossthe diverging discharge orifice causes the already turbulently flowingfuel and air mixture to further expand and atomize. Air which has beenintroduced into the swirl chamber 42 from air passages 13 and tangentialports 37 impinges the diverging fuel-air mixture in a direction parallelto the axis of the diverging discharge orifice 27 as the fuel and airmixture passes through the terminal point of the diverging dischargeorifice 27 to cause a further atomization of the fuel while its passesthrough the discharge orifice 39. By providing a relatively small axialair discharge orifice 20 in axial alignment with the diverging dischargeorifice 27, the air emitted from discharge orifice 20 serves to atomizethe fuel emitted from the swirl chamber 31 and also maincharge orifice27 and the discharge orifice 39 which will Tangential introduction ofthe fuel' provide an air supply or add a significant amount of air to acombustion chamber as might be used in conjunction with the nozzleassembly, thereby aiding fuel combustion within the chamber.

It is appreciated that various minor changes in the construction andarrangement of the parts may be made without departing from the spiritand scope of the invention as hereinafter claimed and further, that theinvention is not limited in its application to liquid fuel atomizingnozzles, the above description merely setting forth a preferredembodiment of the subject invention.

What is claimed is:

1. An air atomizing fuel nozzle assembly comprising a body member havinga fuel supply passage and an air supply passage therein, an outer sleevemember associated with said body member and defining therewith a chamberadjacent said air supply passage and communicating therewith, said outersleeve member having a central bore therein to receive an inner sleevemember, said inner sleeve member having an axial flow air passagetherein which communicates with said chamber and terminates in a firstdischarge orifice, an inner nozzle washer associated with said outersleeve member and cooperating with said inner sleeve member and saidouter sleeve member to define a first swirl chamber therebetween, saidfirst swirl chamber communicating with a discharge orifice in said innernozzle washer, said inner nozzle washer discharge orifice having anoutwardly diverging surface and being substantially in axial alignmentwith said first discharge orifice and axially spaced outwardly therefromsuch that said first discharge orifice terminates at a point in closeproximity to the inner portion of said inner nozzle washer dischargeorifice, an outer nozzle washer associated with said inner nozzle washerand defining therewith a second swirl chamber, said second swirl chambercommunicating with a discharge orifice in said outer nozzle washer, saidouter nozzle washer discharge orifice surrounding said second dischargeorifice and being axially aligned therewith, said' outer nozzle washerdischarge orifice being substantially cylindrical and having a diameterlarger than the outer diameter of said inner nozzle washer dischargeorifice, ports in said outer sleeve member and said inner nozzle washerestablishing communication between said fuel supply passage and saidfirst swirl chamber, said inner nozzle washer ports being tangentiallydisposed to said first swirl chamber, ports in said outer sleeve memberand said outer nozzle washer establishing communication between said airsupply passage and said second. swirl chamber, said outer nozzle washerponts being tangentially disposed to said second swirl chamber, and acap member adapted to secure said outer sleeve member, said inner nozzlewasher, and said outer nozzle washer to said body member in fixed axialalignment whereby fuel emitted from said first swirl chamber is atomizedby air emitted from said first discharge orifice with the resultingfuel-air mixture emitted from said inner nozzle washer discharge orificebeing; further atomized by impinging air emitted from said second swirlchamber thereby creating a more thoroughly atomized fuel-air mixture.

2. An atomizing nozzle comprising an outer sleeve.

member having a central bore therein, an inner sleeve member positionedwithin SBJld central bore, said inner a second swirl chamber, meansproviding interconnecting passages between said first swirl chamber andsaid second swirl chamber, an outer nozzle washer abutting said innernozzle washer and having an axial discharge orifice there through withthe outer end of said inner Washer terminating axially inwardly of theouter end of said outer washer to provide a third swirl chamber axiallyoutwardly of said second swirl chamber, and means pnoviding additionalinterconnecting passages between said outer sleeve member and said thirdswirl chamber.

References Cited by the Examiner UNITED STATES PATENTS EVERETT W. KIRBY,Primary Examiner.

2. AN ATOMIZING NOZZLE COMPRISING AN OUTER SLEEVE MEMBER HAVING ACENTRAL BORE THEREIN, AN INNER SLEEVE MEMBER POSITIONED WITHIN SAIDCENTRAL BORE, SAID INNER SLEEVE MEMBER HAVING AN AXIAL FLOW PASSAGETHERETHROUGH TERMINATING AT ONE END IN A FIRST DISCHARGE ORIFICE, ANINNER NOZZLE WASHER ABUTTING THE END OF SAID OUTER SLEEVE MEMBER ANDHAVING AN AXIAL BORE THEREIN RECEIVING SAID ONE END OF SAID INNER SLEEVEWHEREBY A FIRST SWIRL CHAMBER IS FORMED BETWEEN SAID INNER AND OUTERSLEEVE MEMBERS AND SAID INNER NOZZLE WASHER, MEANS PROVIDINGINTERCONNECTING PASSAGES BETWEEN SAID OUTER SLEEVE MEMBER AND SAID FIRSTSWIRL CHAMBER, SAID INNER NOZZLE WASHER AND SAID ONE END OF SAID INNERSLEEVE MEMBER PROVIDING A SECOND SWIRL CHAMBER, MEANS PROVIDINGINTERCONNECTING